ZIP archive labelled only as iPhone XS, 1.95 MB, with no indication in the name of what it contains. It may hold a schematic, a boardview or reference images for the Apple iPhone XS, so open it to check the actual files. Such materials are used for board-level repair, including tracing power rails, locating shorts and identifying test points on the logic board. Confirm that any documents inside match the board model and revision you are repairing.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @esquematicosparatodos. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip